Vent assemblage



July 13, 1937.

H. A. sTRELoW 2,086,969

VENT AS SEMBLAGE `Filed March 26, 1956 ATTORNEY- Patented July I3, 1937 PATENT owl-FICE VENT ASSEMBLAGE Henry A. strelew, Milwaukee, wie., essie-nor te The Heil Co., Milwaukee, Wis'., a corporation of Wisconsin Y Application Meren 26, 193s, seriei No. 70,983

6 Claims.

` as gasoline and oil.

Generally defined. an object of the present invention is the provision of an improved venti? which is simple, compact and durable in construction, and which is moreover highly eilicient in use.

When relatively volatile liquids such as naphtha or gasoline are being transported in bulk in large containers such as truck tanks, they tend to gasify and thereby create considerable internal pressure within the containers. When such containers are tightly sealed and some of the liquid is withdrawn, a partial vacuum will tend to form above the confined liquid, thereby subjecting the exterior of the tanks to undesirable external pressure. It therefore becomes desirable to provide means for automatically relieving the internal and the counteracting external pressures without introducing fire hazard and also without permitting undesirable escapes of the liquid. While varioustypes of pressure relief and venting devices have heretofore been proposed, most of these prior devices are objectionable, either because they are too complicated, or becausethey' do not function properlyr under all conditions of use. For example, the more .successful of the prior pressure relief valves, em-

body numerous coacting -casing sections which require accurate and costly machining; and the vacuum breaker valves of these prior as- .semblages, which must necessarily be relatively large but sensitive in "operation, are @spring suspended in vertical positions so that these valves will readily open by inertia when the tanks are suddenly displaced in avertical direction as when the trucks pass over irregularities in the road. While the prior assemblages are provided with fire prevention screens, these are usuallilorelief valve assemblagewhich will function to effectivelymeet all conditions of operation, which can be readily manufactured at moderate st,

and which insures maximum safety in actual use.

n Another specific object of the present inven tion is the provision of an improved valve structure having a vent valve so constructed that it 5 will not tend to Open accidentally due to inertia v induced either by sudden displacement .of the valve structure, or by arresting of the motion thereof.

A further specific object of the invention is to l provide an improved pressure relief and vent valve unit provided With a properly located and effective fire prevention screen, and which is alsov thoroughly' protected against damage or injury.

Still another specific object of the invention is 15 the provision of an improved vent assemblage which can be readily'v installed as a unit, and all y parts of which are conveniently accessible for inspection. i

These and other specific objects and advantages Will be apparent from the following detailed description.

A clear conception of an embodiment of the several improved features, and. of the-construction and operation of vent valve assemblages built in accordancev with the invention, may be had by referring to the drawing accompanying and foirming a part of this specification wherein like reference characters designate the same or similar parts in the various views. 3

Fig. 1 is a fragmentary part sectional view of the upper portion of a truck tank and one of the manhole covers associated therewith, vshowing one of the improved vent valve assemblages While `the improved-ventlvalve assemblage is 45 shown and described herein as being 'especially adapted for application tothe manhole covers .of *ruck tanks for transporting relatively volatile liquids, it is not the intent to, thereby unnecessarily restrict the scope or range of use of the in- 50 vention.

Referring to Fig. 1 of the drawing, the truck tank 5 is ordinarily formed of sheet metal and is divided by partitions of usual construction into several liquid confining compartments 6 each of 55 50 seating 23 around the hub 25.

which is provided with a main manhole cover I having a separately removable closure plate 8 associated therewith, the plate 8 being pivotally suspended from a lever 9 swingably attached to the coverl 'I by means of a pivot I0, and the lever 9 being normally held in sealing position by means of a locking latch mechanism II of well known construction. 'I'he improved valve unit is detachably secured to the central portion 10 of the closure plate 8, and while this assemblage is normally disposed within the compartment 6, `it is also accessible from without by merely releasing the latch mechanism II and by subsequently swinging the plate 8 away from its seating I2 with the aid of the suspension lever 9.

The new valve assemblage is shown in detail in Figs. 2 and 3, and comprises in general a onepiece main valve casing I4 having four independently functioning valves I5, I6, i1, i 8 and a fire prevention screen I9 associated therewith. The

main casing i4`is of substantially hollow cylindrical formation, and has an upper integral threaded nipple 20 adapted for coaction with a central threaded opening in the closure plate 8, and with a combined clamping and cover member 2| normally disposed above the plate 8 and provided with passages 22 connecting the interior ofthe casing I4 and nipple 20 with the ambient atmosphere. 'I'he casing I4 may thus be firmly but removably and adjustably suspended from the closure plate 8 within the upper portion of the liquid confining compartment 6, by means of the integral nipple 20 and the clamping member 2l, the latter also serving to'pro- 3 tect the valve assembly against tampering and ingress of dirt or other foreign matter.

The large high pressure' relief valve I5 is of the poppet type and is disposed to move vertically within the lower end of the valve casing I4.

This vvalve I5 coacts with a seating 23 having screw threaded coaction with vthe internally threaded end of the casing I4, thus permitting convenient removal of the valve I5 and its seating 23 as a unit. 'I'he stem 24 of the valve I5 is guided in a central hub 25 formed integral with the seating 23, and the v alve- I5 is normally urged against its seat by means of a relatively strong compression spring 28 coacting with the stem 24 througha washer 2I` and reacting against the The strength of the spring 25 mustbe suiiicient to retain the valve .I5 closed in case the tank 5 is inverted and the valve I5 is thus subjected to the full pressure of the liquid within the compartment 6,

but abnormally high pressures created within this compartment will compress the spring 25 sufiiciently to open the valve I5 and thereby quickly relieve such pressures.

The small internal pressure relief valve I6 and the automatic check valve I1 are mounted in an auxiliary casing 28 which is insertable within lthe main valve casing I4 through a side opening therein, and is adapted to be fastened to the main casing by means of cap screws 2l as shown in Figs. 2 and 3. The valve I8 is also of the poppet type and normally coacts with a valve seat 3l, being pressed against this seat by meansfof a relatively iight coil spring 3i. This valve I5 normally functions to quickly and automatically relieve slight internal pressures developed within the compartment 8, which are insumcient to vopen the larger valve I l. The ball checkvalve I1 is normally open, but is'adapted to move by er" gravity into engagement with-its seat Ito positively prevent escapef of liquid or gas past the small valve I 6, when the tank 5 is inverted. It is to be noted, that the provision of the check valve I1 is necessary due to the fact that the spring'3l coacting with the small pressure relief valve I6 is insufficient to resist opening of the 5 latter'by the liquid pressure acting thereagainst in case of inversion of the tank 5; and since the valves I6, II cooperate in the manner indicated, they may be readily confined in a common casing 28. l0

The vacuum relief valve I8 coacts with a valve seat 33 formed directly on the side of the main valve casing I4 opposite to the side to which the auxiliary casing 28 is attached, and has an integral stem 34 which is slidable in a guiding hub 15 35 formed integral with the casing I4. This valve I8 is also of the poppet type, and is normally maintained in closed position by ymeans of a coil spring 36 one end of which coacts with a washer 3l secured to the stem 34 and the opposite end 20 of which reacts against the casing I4 as shown in Fig. 2. The valve I8 is adapted to open into the compartment 6 to admit air from the outside, whenever the pressure Within this compartment drops below atmospheric suiiicient to i" compress the spring 36; and it is to be noted that by locating the valve I8 on the side of the casing I4 diametrically opposite to the casing 28, machining of thecasing I4 is greatly facilitated. x The horizontal disposition of the axis of the valve "0 I8 is also important, since a suitable spring 36 may thus be utilized without danger of having the valve I8 opened at undesirable times by the inertia thereof. The valves I5, I6, IT, I8 just described obviously function independently of each other and perform their functions automatically in order to meet predetermined operating conditions. The lire prevention screen I9 is secured within the main valve casing I4 at a point between the valves 40 I5, I6, I1, I8 and the outlet passage leading to the ambient atmosphere, and the valve assemblage may obviously be positioned so that the axis of the valve I8 extends either longitudinally y or transversely of the tank 5. During normal op- 40 eration of the improved valve assemblage, one of which is normally applied to the manhole cover of each compartment 8 of the tank 5, the small pressure relief valve I6 will normally opr erate to release slight internal pressures pro- 0 duced by volatilization of the confined liquid or otherwise; and the vacuum relief valve I8 will likewise operate to counteract all external pressures caused by withdrawalv of liquid from within fr the compartment 6. When the internal pressure "o relief valve I 8 becomes inoperative or when the 4capacity thereof is insufficient to meet requirementa-the larger internal pressure relief valve I5 `will automatically function to relieve the internal pressure, this valve being of sumcient capacity to prevent dangerous internal pressures from being created within the compartment 5 under any conditions. The larger relief valve I5 and the vacuum relief valve Il, will remain closed during accidental inversion of the tank 5, and if 65 the small internal pressure relief valve Il opens upon inversion of the tank 5, liquid will be prevented from escaping from within the compartment 8 by virtue of the fact that the ball check valve I1 will automatically close by gravity. 70

Fromthe foregoing detailed description it will be apparent that the present invention provides a simple, compact and highly eiiicient valve assemblage for automatically relieving both internal and external pressures on the tank 5, underany condition of operation, without permitting un- 'desirable escape of liquid from within the com-V partment 6. The improved valve assemblage can be readily manufactured and installed, and all of the independently functioning valves I5, I6, I1, I8 are readily accessible by virtue of their detachable mounting in the main casing I4. The ooacting valve I6, I1 may be applied to and removed from the casing I4 as a unit, andthe horizontal disposition of the vacuum valve I8 prevents this valve from `being opened by inertia during transportation of. the truck tank 5. The location ofthe fire prevention screen I9 between the valves and the exterior of the tank, permits this screenyto most effectively perform its function, and the entire valve assemblage is effectively protected by the clamping member 2I.

It should be understood that it is not desired to limit the invention to the exact details of construction and to the precise mode of operation herein shown and described, for various modifications within the scope of the claims vmay occur to persons skilled in the art.

I clairnty v 1. A vent valve assemblage especially applicable as a single unit to liquid transporting tanks,

said assemblage comprising, a one-piece casing 'having a single upper suspension portion, a vertically movable high pressure relief valve carried by the lower portion of said casing, a horizontally movable low pressure relief valve carried by an upper side portion of said casing, and a spring pressed vacuum relief valve carried by the opposite upper side portion of said casing, said vacuum relief valve being movable along a substantiallyhorizontal axis in alinement with said low pressure relief valve. l

2. A 'vent valve assemblage especially applicable as a.l single unit to liquid transporting tanks,

'said assemblage Icomprising, a substantially cylindrical hollow casing having an upper suspension portion provided with an opening communieating with the atmosphere, a high pressure relief valve detachably secured to the lower end of vsaid casing and movable along the central vertical casing axis, a low pressure relief valve detachably secured to an upper Aside portion of said casing and movablev along a substantially horizontal axis, and a vacuum relief valve carried by the opposite upper side portion of said casing and movable along the axis of movement of said low pressure valve.

3. A unitary vent valve assemblage for movable tanks, comprising, a hollow one-piece casing formed for suspension within the tank 'and having an opening through its suspension portion communicating with the atmosphere, a high internal pressure relief valve carried by said casing, a vacuum relief valve carried by said casing independently of said high pressure valve, an auxiliary casing carried by said hollow casing in alinement with said vacuum relief valve but independently of said valves, and a lowvpressure relief valve and a check valve confined within said auxiliary casing, said auxiliary casing being removable to permit access to said vacuum relief valve.

4. A unitary vent valve assemblage for movable receptacles, comprising, a casing having an upper' suspension portion, a vertically movable high pressure relief valve carriedby the lower portion of said casing, a horizontally movable. low pressure relief valve carried by a side portion of said 'casing between said suspension portion and said high pressure relief valve, and a vacuum relief valve carried by the opposite side portion of said casing and being movable in substantial alinement with said low pressure relief valve.

5. A unitary vent valve assemblage for movable receptacles, comprising, a hollow casing having -an upper suspension portion provided with an opening connecting the casing interior With the atmosphere, an upwardly movable high pressure relief valve having a seat secured'to the 'lower' end of said casing, a low pressure reliefvalve secured to one side of said casing between said suspension portion and said high pressure relief valve seat, and a vacuum relief valve carried by the opposite side of said casing, said low secured to ther lower end of said casing, a low pressure relief valve detachably secured-to one vside of said casing between said suspension portion and said high pressure valve seat, and a vacuum relief valve having a supporting' seat detachably secured to the opposite side of said casing, said low pressure relief valve andL said vacuum relief valve being movable horizontally in substantial alinement with each other.

v HENRY A. STRELOW. 

